Vacuum Sintering of Stainless Steel Filter Element

The sintering and heat treatment process of the stainless steel filter element includes charging, vacuuming, degassing, heating, argon filling, heat preservation, cooling and discharging. The stainless steel filter element puts the blank into a tray or a data box for sintering. The pallet or data box is made of high temperature resistant material, such as molybdenum sheet.

The stainless steel filter element vacuum unit removes the air in the sintering chamber and the gas attached to the blank. After the vacuum pump is sent to the high vacuum, the high vacuum pump is turned on. The general requirement of two-stage vacuum pumping to 1.3X10-1Pa.

The stainless steel filter element is electrically heated and continuously pumped at a temperature of 400 to 500°C. This method can eliminate the residual stress of the briquette, and gradually differentiate and evaporate the adsorbed gas on the surface of the briquette and the organic media such as lubricant and granulator added to the briquette.

After the stainless steel filter element is degassed, the furnace is heated to the sintering temperature. Regarding different materials, the sintering temperature is also different. The sintering temperature should be accurately measured and controlled. Too high temperature will make the product soft and deformed, the particles will be rough and even useless. When the sintering temperature is too low, the compaction speed of the green compact becomes slower, the sintering time is extended, the equipment utilization rate decreases, and the product function cannot meet the requirements.

With the increase in temperature of the stainless steel filter element, the gas removal of the blank guess tends to be completed under vacuum. Regarding the sintering in the maintenance atmosphere, argon should be filled into the sintering chamber to complete the sintering in the maintenance atmosphere. After filling with argon, the vacuum unit is stopped to reduce power consumption.

The stainless steel filter element stays at the sintering temperature for a period of time, so that the compact during the sintering process is completely densified, and the pores given to the crystal are shortened, eliminating and changing the time of satisfaction. The length of the holding time depends on the scale and scale of the sintered product. The appropriate sintering temperature and persistence time can be determined by measuring the density of the product.